Composite stopper with controlled permeability

ABSTRACT

A composite stopper for closing bottles, in particular wine bottles, comprising a body made of a compressible material such as cork, provided at least at its end facing the contents of the bottle to be closed with matching element forming a joint. The element ( 25 ) is made from a substantially incompressible elastomer, filling up a cavity arranged circular in shape and a concentric position in the end surface ( 24 ) of the stopper body ( 22 ) and having a volume such that the element, under the effect of compression whereto the stopper body is subjected when the bottle is closed, is elastically deformed at the front of the end surface, so as to produce after closure, at the front of the cork body end surface, a sealing joint covering the whole of the end surface and in contact the bottle neck inner surface ( 26 ). The invention is useful for closing bottles of sparking or non-sparking wine.

FIELD OF THE INVENTION

The present invention relates to a controlled permeability compositestopper for stopping bottles, in particular bottles of wine, having abody made from a compressible material such as cork, fitted withcomplementary means forming a seal at least at the end facing toward thecontent of the bottle.

BACKGROUND OF THE INVENTION

Stoppers of the above type are described in French patents Nos. 983 488,1 068 263, 1 100 335, 1 338 657, 1 573 650, 2 644 142 and 2 736 036 andEuropean patent application EP-A-0 532 367, for example. In the abovedocuments, the complementary seal means can be sheets, films, coatings,disks, etc. of synthetic material, rubber, elastomer, for examplesilicone elastomer, covering at least the whole of the end face of thestopper facing toward the content of the bottle to be stopped.

The use of cork in stopping wines is related to the exceptionalqualities of the material, namely its virtual freedom from rotting,compressibility, resilience, sealing effect, easy machining from rawcork-oak bark, aptitude for gaseous exchange, durability, etc.

However, cork is also the cause of certain organoleptic problems due tointeraction with the wine. Also, given the fact that it is machined, thetolerances that apply and defects that are sometimes difficult todetect, despite rigorous inspection, a cork stopper is sometimesincapable of providing a total liquid seal at the cork-glass interface,whence the well-known “leaky bottle” phenomenon.

The proposals in the patents cited above are not satisfactory, inparticular because the complementary means provided on at least one endface of the stopper cause problems when the stopper is pushed into thebottle neck. Because the means referred to cover the whole of the endface of the stopper facing toward the content of the bottle, it is thematerial from which the complementary means are made that comes intocontact with the end of the neck when the stopper is pushed in aftercompressing it radially. Because the material from which thecomplementary means are made is incompressible, unlike the corkconstituting the body of the stopper, the complementary means are notsubjected to the same deformation as the body of the stopper, with theattendant risk of imperfections such as creasing, cracking, peeling,etc. In this regard, it should be noted that stopping a bottle includesan operation of radially compressing the stopper, which has a diameterof 24 mm for still wine or 31 mm for sparkling wine, to a diameter of15.5 mm, in jaws, the compressed stopper then being pushed into thebottle neck, where it expands to the inside diameter of the neck, whichis 19 mm for a still wine or 17 mm for a sparkling wine.

Pressing in stoppers compressed in this way is not a problem if thestoppers are made entirely of cork.

It is a problem, however, if the end face of the stopper facing towardthe content of the bottle to be stopped is covered with complementarymeans in the form of a synthetic material sheet, film, disk or coating.

It is then the complementary means that first come into contact with theend of the neck and are stressed to the point of being damaged. Also,the material from which the complementary means are made has a highcoefficient of friction relative to the glass of the bottle neck, unlikethe cork of conventional stoppers, which are incidentally often treatedto slide more easily.

For all the above reasons, the composite stoppers disclosed in thedocuments previously cited have in practice not become the norm forstopping wine.

SUMMARY OF THE INVENTION

The present invention is directed to a composite stopper which remediesthe disadvantages of the usual stoppers made entirely of cork and alsothe disadvantages of the composite stoppers disclosed in the prior artpatents cited above.

A composite stopper in accordance with the invention for stopping theneck of bottles, in particular bottles of wine, comprises a body madefrom a compressible material such as cork, fitted with complementarymeans forming a seal at least at its end facing toward the content ofthe bottle to be stopped, characterized in that said means comprise amember made from a substantially incompressible elastomer, virtuallycompletely filling a circular section cavity formed concentrically in anend face of the stopper body so that a ring of the end face of thestopper body remains around said cavity, which has a volume such thatsaid member, due to compression of the stopper body during stopping, iselastically deformed forward of said end face, after stopping, so as toestablish after stopping, forward of said end face of the stopper body,a seal covering the whole of said end face and in contact with theinside face of the bottle neck.

In accordance with the present invention, before the stopper iscompressed, the substantially incompressible elastomer member fillingthe cavity in the end face does not cover the whole of the end face ofthe stopper, but leaves a ring of cork between its outside edge and theoutside edge of the end face.

The ring of cork enables the bottling operation to be carried out in theusual way, without modification. Because the relaxation time of theelastomers used is greater than one second and, in the usual bottlingmachines, the time between compressing the stoppers and pushing them isgenerally less than one second, the elastomer does not have time todeform completely, in response to the compression of the body of thestopper, before the stopper is pushed into the bottle neck. When thestopper is pressed in, it is therefore the outside edge of the ring ofcork which comes into contact with the top of the neck of the bottle,and the conditions under which the stopper slides in the neck aretherefore the same as with stoppers made entirely of cork.

In other words, the stopping operation is in no way modified by thepresence of the elastomer member on the stopper according to theinvention.

The volume (diameter and depth) of the cavity filled with elastomer canvary, in particular as a function of the degree of compression of thestopper body, which varies according to the type of wine to be stopped.However, the cavity is preferably at least 1 mm deep at its deepestpoint, before compression.

The elastomer member is shaped to leave a ring with a (radial) width ofat least 1 mm on the end face of the stopper body before compression ofthe stopper body.

Said cavity can have a substantially cylindrical shape, for example, butit preferably has a divergent shape, i.e. a diameter that increases fromthe bottom toward the open side.

The elastomer constituting the member filling said cavity is preferablya foodstuffs grade silicone elastomer.

The elastomer member is preferably molded and cross-linked before it isfitted into the cavity, but can also be obtained by molding andcross-linking the raw elastomer in the cavity of the stopper body.

In one embodiment the elastomer can be an elastomer permeable to smallgas molecules such as H₂, N₂, O₂, CO₂ and impermeable to large moleculessuch as molecules with aromatic cycles, including those responsible forthe “corked taste”. The seal consisting of the elastomer membertherefore does not degrade in any way the exchange of small-moleculegases, leaving the cork of the stopper body to fulfill its usual role ofcontrolling gas exchange on its own.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative and non-limiting embodiments of a composite stopper inaccordance with the invention are described in more detail hereinafter;in the drawings:

FIGS. 1 and 2 show a stopper in accordance with the invention forsparkling wine, before radial compression of the stopper and afterpushing the stopper into the bottle neck,

FIGS. 3 and 4 are corresponding views of a stopper for still wine, and

FIGS. 5 and 6 are corresponding views of a preferred embodiment of astopper according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a stopper 1 intended for stopping a bottlecontaining sparkling wine, for example champagne, has a stopper body 2of natural or reconstituted cork, or a mixture of the two, in the shapeof a cylinder or a rectangular parallelepiped with rounded edges, andhas two plane and parallel end faces. There is a cup-shaped ordome-shaped concentric circular cavity 3 in one end face, the edge ofthe cavity 3 being spaced from the edge of the corresponding end face sothat a ring 4 of the plane end face of the stopper body remains aroundthe cavity 3. The cavity 3 is filled with a substantially incompressibleelastomer 5, for example a silicone elastomer, which is flush with theend face in the example shown.

FIG. 2 shows the stopper 1 from FIG. 1 after it has been pushed into abottle neck 6. To this end, the cork stopper 1 is radially compressed inthe usual way over the portion of its length intended to be pushed intothe bottle neck 6, which reduces its diameter from 31 mm to 15.5 mm.This radial compression is followed in less than one second by pushingthe compressed part of the stopper 1 into the bottle neck 6. Because ofthe radial compression of the stopper body 2, the incompressibleelastomer member 5 is subjected, after a relaxation time ofapproximately one second, and therefore after the stopper 1 has beenpushed into the bottle neck 6 and expanded to the inside diameter (17mm) of the neck, to elastic deformation forward of the end face in whichthe elastomer member 5 is disposed, so that the member 5 assumes theshape inside the bottle neck 6 shown in FIG. 2, projecting radiallyoutwards onto the ring 4 until it touches the inside face of the neck 6,so establishing a seal over the whole of the end face of the stopper 1.

Because of the relaxation time of the elastomer of the member 5, pushingthe stopper 1 into the bottle neck 6 is not modified compared to pushingin a stopper made entirely of cork because, during pushing in, only thecork of the stopper 1 comes into contact with the glass of the neck 6.

FIG. 3 shows a stopper 11 for still wine, having a cork stopper body 12which has dome-shaped or cup-shaped cavities 13 a, 13 b in respectiveend faces. Each cavity 13 a, 13 b is circular and is formedconcentrically in the corresponding end face so as to leave around it aring 14 a, 14 b of cork in the plane of the end face. Each cavity 13 a,13 b is filled with a substantially incompressible elastomerconstituting, in the example shown, a member 15 a, 15 b with a convexoutside face.

In FIG. 4, the stopper 11 from FIG. 3 has been pushed into a bottle neck16 after radial compression of the stopper 11 has reduced its diameterfrom 24 mm to 15.5 mm. After a relaxation time of approximately onesecond, the radial compression to which the cork of the stopper body 12is subjected by elastic compression causes axial deformation of theincompressible members 15 a, 15 b, as a result of which the members 15a, 15 b adopt the shape shown in FIG. 4. Each member 15 a, 15 b expandsradially, forward of the corresponding end face of the stopper body 12,which has expanded to the inside diameter (17 mm) of the neck, until itcomes into contact with the glass of the neck 16 of the bottle, where itconstitutes a seal for the liquid contained in the bottle.

The second seal created by the member 15 b at the free end of the neck16 protects the cork of the stopper body 12 from mildew, worms and otherforms of external aggression.

A circular cavity, regardless of its shape, can be machined directlyinto the end face of the stopper body. To make a cylindrical cavity, forexample in the case of a stopper body consisting of a plurality ofdisks, it is possible to remove the center of the last disk (so that itis converted into a short tube) and stick it to the remaining part ofthe stopper body.

The elastomer member can be made by molding and cross-linking “raw”elastomer directly in the cavity, for example, but it can equally wellbe molded and cross-linked separately and then mounted and fixed in thecavity, for example stuck or clipped in the cavity.

To enable the elastomer member to fulfill its functions, the open sideof the cavity can occupy almost all of the end face of the stopper body,but here, before the stopper is compressed radially, the member leaves aring 4 whose (radial) width is at least 1 mm.

The width of the ring 4 can be in the range from approximately 1 mm toapproximately 2 mm in the case of a 24 mm diameter stopper for stillwine, for example, or in the range from approximately 3 mm toapproximately 7 mm for a 31 mm diameter stopper for sparkling wine.

In the preferred embodiment shown in FIGS. 5 and 6, which here appliesto stopping a bottle neck 26 for still wine, but which can be usedpractically without modification for stopping bottles of sparkling wine,the cavity 23 formed concentrically in one end face of the body 22 of astopper 21, leaving an outside ring 24 of said end face, has a diameterthat increases from the bottom of the cavity toward its open side, sothat the cavity has a “trumpet-shaped” profile. In other words, theflanks of the cavity are convex rather than concave, as in the previousexamples.

Furthermore, note that the cavity 23 has an annular groove 27 in itsbottom which increases its depth. The preformed molded elastomer member25 has an outside part 28 in the form of an annular bead which protectsafter the member 25 is placed in the cavity 23, at least partly over theend face of the stopper body 21, the central part 29 of the outside faceof the elastomer member 25, set back relative to the bead 28, beingsubstantially level with the end face (ring 24) of the stopper body(before the latter is compressed).

Note also that the member 25 is here fixed to the stopper body 22 onlyat the location of the annular rib 30 projecting from its bottom, whichnests in the groove 27 of the cavity 23.

This encourages elastic deformation of the member 25 forward of the endface of the stopper body, after stopping the neck 26 after radiallycompressing the stopper body 22, the member 25 being able to slideeasily on the flanks of the cavity 23, so that after stopping the bead28 as a whole is pressed perfectly against the inside face of the neck26, forward of the ring 24, as shown in FIG. 6.

Finally, the part of the member 25 nested in the cavity 23, andtherefore subjected to elastic deformation in response to radialcompression of the stopper body 22, here has a smaller diameter than inthe previous examples, corresponding to approximately 50%, or even less,of the diameter of the stopper body before compression, depending on thedegree to which the stopper is compressed. On the other hand, the(axial) thickness of the nested part of the member 25 is greater, andcan be equal to at least 3 mm, for example, for a 24 mm diameter stillwine stopper or for a 31 mm diameter sparkling wine stopper.

Note that the elastomer used in the invention, defined as being“substantially incompressible”, is an elastomer which deformselastically without significantly decreasing its volume when it iscompressed.

In the context of the invention, the volume of the elastomer isadvantageously reduced by less than 15%, and preferably less than 10%.

The elastomers that can be used in the context of the invention includein particular hot-vulcanized silicone elastomers (EVC), for examplefoodstuffs grade polydimethyl/vinylmethylsiloxane (VMQ), which can beshaped by molding and has a Shore A hardness in the range fromapproximately 35 to approximately 70. Conclusive tests have been carriedout with S 60 i 59×platinum-catalyzed EVC from VERNERET, LAMOTHE-AUX-AULNAIES, F-89120 CHARNY, FRANCE, for example, which has aShore A hardness of 60.

Conclusive tests have also been carried out with S 60 i 01 L liquidsilicone elastomer from the same company, which has a Shore A hardnessof 60.

The above silicone elastomers, which are permeable to small gasmolecules, can be replaced with B 50 i 20 B foodstuffs grade chlorinatedbutyl rubber from the same company, or a corresponding butyl rubbercontaining bromine, for example, which has a Shore A hardness of 50. Theabove rubbers have the particular feature of being totally impermeable,even to small gas molecules. Stoppers equipped with seal members madefrom the above rubbers can be used in particular for wines to beconsumed young, i.e. wines that do not improve through aging.

What is claimed is:
 1. A composite stopper for stopping the neck ofbottles of wine, comprising: a stopper body of generally cylindricalshape made from an elastically compressible material and having at leastone circular flat end face, said stopper body having a circular cavitywith a bottom formed concentrically in said end face, the diameter ofthe outer edge of said cavity being smaller than the diameter of theouter edge of said end face in the uncompressed condition of the stopperbody such that a ring of said end face remains between the outer edge ofsaid cavity and the outer edge of said end face; and a circular membermade from an elastomer which is liquid impervious and which iselastically deformable but substantially incompressible, said circularmember being fitted into said cavity such as to completely fill saidcavity and to leave uncovered at least an outer portion of said ring ofsaid end face of the stopper body, said cavity having such a volume thatsaid member, upon radial compression to which the stopper body issubjected upon stopping, is elastically deformed forward of said endface, so as completely to cover said end face after stopping.
 2. Astopper according to claim 1, wherein said cavity is at least 1 mm deepat its deepest point.
 3. A stopper according to claim 1, wherein saidcircular member is shaped to leave uncovered a ring with a radial widthof at least 1 mm on the end face of the stopper body before compressionof the stopper body.
 4. A stopper according to claim 1, wherein saidelastomer is a silicone elastomer.
 5. A stopper according to claim 1,wherein said elastomer is an elastomer permeable to small gas moleculesincluding H₂, N₂, O₂, and CO₂ and impermeable to large moleculesincluding molecules with aromatic cycles.
 6. A stopper according toclaim 1, wherein said circular member is molded and cross-linked beforeit is mounted and fixed in said cavity.
 7. A stopper according to claim1, wherein said circular member has a part in the form of an annularbead projecting forward of said end face of the stopper body before thestopper body is compressed.
 8. A stopper according to claim 1, whereinsaid cavity has a divergent shape with convex flanks.
 9. A stopperaccording to claim 1, wherein said circular member is fixed to thestopper body only at the bottom of the cavity.
 10. A stopper accordingto claim 9, wherein said circular member has an annular rib on itsbottom and the cavity has an annular groove in its bottom in which saidrib is nested and fixed.
 11. A stopper according to claim 1, whereinsaid stopper body is made from cork.
 12. A stopper according to claim 1,wherein said cavity has a width greater than its depth.